HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4780
PERIOD COVERED: 5am January 28 - 5am January 29, 2009 (DOY
029/1000z-030/1000z)
OBSERVATIONS SCHEDULED
WFPC2 11316
HST Cycle 16 & Pre-SM4 Optical Monitor
This is a continuation of the Cycle 15 & pre-SM4
Optical Monitor, 11020.
Please see that proposal for a more complete description
of the
observing strategy. The 6 visits comprising this proposal
observe two
single standard stars with WFPC2/PC in order to establish
overall OTA
focal length for the purposes of focus maintenance. The
goal of this
monitoring before SM4 is to establish a best estimate of
the OTA focus
entering SMOV.
WFPC2 11944
Binaries at the Extremes of the H-R Diagram
We propose to use HST/Fine Guidance Sensor 1r to survey
for binaries
among some of the most massive, least massive, and oldest
stars in our
part of the Galaxy. FGS allows us to spatially resolve
binary systems
that are too faint to observe using ground-based, speckle
or optical
long baseline interferometry, and too close to resolve
with AO. We
propose a SNAP-style program of single orbit FGS TRANS
mode observations
of very massive stars in the cluster NGC 3603, luminous
blue variables,
nearby low mass main sequence stars, cool subdwarf stars,
and white
dwarfs. These observations will help us to (1) identify
systems suitable
for follow up studies for mass determination, (2) study
the role of
binaries in stellar birth and in advanced evolutionary
states, (3)
explore the fundamental properties of stars near the main
sequence-brown
dwarf boundary, (4) understand the role of binaries for
X-ray bright
systems, (5) find binaries among ancient and nearby
subdwarf stars, and
(6) help calibrate the white dwarf mass - radius relation.
WFPC2 11962
A New Supernova in the Antennae; Narrowing in on the
Hubble Constant and
Dark Energy
A measurement of the Hubble constant to a precision of a
few percent
would be a powerful aid to the investigation of the nature
of dark
energy and a potent "end-to-end" test of the
present cosmological model.
In Cycle 15 we constructed a new, streamlined distance
ladder utilizing
high-quality type Ia supernova data and observations of
Cepheids with
HST in the near-IR to minimize the dominant sources of
systematic
uncertainty in past measurements of the Hubble constant
and reduce its
total uncertainty to a little under 5%. Here we propose to
exploit this
new route with a rare opportunity to begin reducing the
remaining
uncertainty. SN 2007sr in the Antennae (NGC 4038/9) is the
rare SN Ia
which is suitable for increasing the precision of small
calibration
sample of
Cepheids are within range of observing with WFPC2 (and
NICMOS, should it
return to life). But we need to act fast as the window of
long
visibility and fixed orient runs from mid-early December
2008 to early
March 2009. We request 34 orbits with WFPC2 to find the
Cepheids in the
SN host. We also request 16 orbits to observe the Cepheids
we find with
Camera 2, F160W if NICMOS becomes available by April 2009
. (If NICMOS
does not return we would forgo these observations and ask
the TTRB to
let us make them with our own WFC3-IR allocation, though we
much prefer
the smaller pixel size of NIC2).
WFPC2 11966
The Recent Star Formation History of SINGS Galaxies
The Spitzer Legacy project SINGS provided a unique view of
the current
state of star formation and dust in a sample of galaxies
of all Hubble
types. This multi-wavelength view allowed the team to
create current
star formation diagnostics that are independent of the
dust content and
increased our understanding of the dust in galaxies. Even
so, using the
SINGS data alone we can only make rough estimates of the
recent star
formation history of these galaxies. The lack of high
resolution
observations (especially U-band and H-alpha) means that it
is impossible
to estimate the ages of young clusters. In addition, the
low resolution
of the Spitzer and ground-based observations means that
what appear to
be individual Spitzer sources can actually be composed of
many
individual clusters with varying ages. We need to know the
ages, star
formation histories, and extinction of these individual
clusters to
understand how these clusters form and age and thus
influence the
evolution of the galaxy. In this proposal we address this
missing area
of SINGS by obtaining high-resolution WFPC2 UBVI &
H-alpha observations
to not only accurately locate and determine the ages of
the young
stellar clusters in the actively star forming SINGS
galaxies but to also
address a variety of other scientific issues. Over 500 HST
orbits and
500 hours of Spitzter observing time have been dedicated
to observations
of the SINGS sample. But the HST observations have not
been systematic.
By adding a relatively small fraction of this time for
these requested
observations, we will greatly enhance the legacy value of
the SINGS
observations by creating a uniform high resolution
multi-wavelength HST
archive that matches the quality of the lower resolution
SINGS archive.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS: (None)
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
03
03
FGS
REacq
08
08
OBAD with Maneuver
24
24
SIGNIFICANT EVENTS: (None)